1. Field of the Invention
The present invention relates to an auto disc changer which can store a large number of audio discs and play back the discs one at a time, and in particular, to an auto disc changer in which a disc storage position is mapped, which mapping data can be recorded.
Further, the present invention relates in particular to an auto disc changer which can continue a check mode recording the presence of the discs when the power is turned off.
Moreover, the present invention relates in particular to an auto disc changer which can display information about whether or not a specified disc is already stored in a specified disc storage position.
Moreover, the present invention relates in particular to an auto disc changer which can display the presence of the discs in order to allow the user to easily and quickly store and remove the discs.
2. Description of the Related Art
In general, auto disc changers currently in use with a disc playback operation comprise a disc tray which removes discs from and loads discs into the unit (disc removal and loading means), a stocker which stores a number of discs inside the unit (disc storage means), a carriage which transfers the discs to and from a predetermined storage position in the stocker (disc carriage means), and a control means which controls the loading, and removal operations and the transfer of the discs.
When a unit has a storage capacity of only two or three discs, a user is able to see the stored discs in the unit.
With the auto disc changers which store no more than ten discs, the stored discs are easily checked without an information display indicating at which disc storage position a specified disc is stored, because only a small number of discs are stored, and accordingly, a user does not ordinarily make a mistake with regard to the disc storage position.
However, when storing a much greater number of discs than are currently storable in a conventional changer, the user cannot easily confirm disc storage positions by merely looking. This is due to the construction of such large capacity changers in which the gaps between the disc storage positions are made narrow so that a large number of discs can be stored in a limited space.
In this case, if the status (presence or absence) of the discs in the disc storage positions are checked and such data can be provided for the user, the user can correctly determine whether or not a disc has already been stored in a specified disc storage position, with reference to the data, and can know in advance, for example, whether or not a disc storage position is empty.
Such check mode is normally performed at the same time the power is turned on, and the time required for such check depends on the disc storage capacity of the changer. If the unit can store up to 100 discs, the check may take several minutes. During such time, the power switch may be (accidentally) turned off.
If the power is turned off during the check mode, the check mode is terminated because power is not supplied to the control block with the microcomputer which drives the check mode, and the recorded data is lost.
When the power is again turned on, the check mode must be re-started. The user cannot operate other changer functions such as disc play or storage, until the check mode is completed. This delay may irritate the user.
Further, when the user tries to store a disc, he must specify the disc storage position. However, a disc may already be stored in the specified disc storage position, therefore it would be helpful to be able to determine the status of the disc storage position ahead of time. Otherwise, the user can not know that the disc storage is unavailable until he begins to operate the unit. A storage operation for the occupied disc storage position is useless, unnecessary burdening the mechanical parts.
When a disc is removed, the empty disc storage position may also be specified. Otherwise, the user may try to play back from an empty disc storage position and not recognize his mistake in specification until the disc tray is opened. It would be convenient for the user to be informed in advance that a specific disc storage position is empty.
The above would be particularly useful for an auto disc changer which can store a large number of discs, for example up to 100, because operations in which a disc is stored or removed are repeated many times.
Moreover, if the status (full or empty) of the discs storage is displayed during the operation mode, the operations in which the disc is stored and removed can be smoothly and quickly performed.
For example, if only the empty disc storage positions are displayed successively, the user can specify the disc storage easily, and the disc can be smoothly and quickly stored into the storage position.
Currently, because the number of the discs which a typical changer can store is small, such means described above have not been provided.